California Clapper Rail (image) University of California - Davis Share Print E-Mail Caption A California Clapper Rail stands beside invasive Spartina, a salt marsh cordgrass, in San Francisco Bay. The endangered bird is threatened by both the removal and existence of the invasive plant. Credit Robert Clark Usage Restrictions Provide credit. Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.